<!DOCTYPE html>
<html>

	<head>
		<meta charset="UTF-8">
		<title>optgroup</title>
	</head>

	<body>
		<select>
			<optgroup label="长三角">
				<option value="合肥">合肥</option>
				<option value="上海">上海</option>
			</optgroup>
			<optgroup label="其他">
				<option value="四川">四川</option>
				<option value="重庆">重庆</option>
			</optgroup>
		</select>
	</body>

</html>